The invention relates to a device for supplying a hydraulic medium to a drive element rotatably mounted in a transmission case.
In general, drive elements rotatably mounted in a transmission case—only one example being the pulley set of continuously variable transmission in a motor vehicle, with a hydraulically adjustable loose pulley which can be axially moved relative to the fixed pulley—are transmitted by way of channels in the shaft which bears the drive element by a coaxially configured element which is connected to the hydraulic control. In particular, when several separate channels are necessary for hydraulic control, this results in a significant production engineering effort and a considerable weakening of the indicated shaft due to the required shaft bores.
The object of the invention is to propose a device of the generic type which enables reliable hydraulic supply of a drive element without shaft holes.
The drive element of the invention is nonrotatably connected to the other element and that the contact connection is at least one unthreaded conduit which is inserted tightly into the two channels and which extends directly from the element to the drive element. At least one unthreaded conduit turns with the element which supplies the hydraulic medium; shaft bores can accordingly be omitted. Furthermore, at least one unthreaded conduit forms a connection which to a limited degree allows universal movements and axial compensation between the drive element and the other element; this results in supply of the hydraulic medium to the drive element which is reliable even with unfavorable tolerance pairings and operating conditions. (temperature, load) or axial slip. Another major advantage is that if necessary the supplying element can be a component of the transmission which also performs other functions (for example, routing the hydraulic medium through a coaxially adjacent gear which turns with the drive element).
At least one unthreaded conduit can extend radially within a roller bearing which is provided between the drive element and the adjacently located element. This makes possible supply of the drive element by way of at least one unthreaded conduit even if support is indicated between the drive element and the other element for transmission engineering purposes.
Preferably the inner ring of the roller bearing can sit on the neck of the drive element and at least one unthreaded conduit can run in a corresponding recess of the neck. The unthreaded conduit can thus be partially integrated into the drive element without added construction effort and space consumption.
Simple axial locking is achieved by the unthreaded conduit being provided with a radial projection by means of which it is held on the front between the inner ring of the roller bearing and the following drive element.
Furthermore, for easy installation of the transmission element the unthreaded conduit on the two ends can bear gaskets for sealing with the adjoining channels in the drive element and the other element. This makes it possible to easily assemble the transmission elements and enables routing of the hydraulic medium which is insensitive to vibrations and which is guided hermetically sealed even in the event of limited universal and axial relative movements.
Especially preferably provision can be made for several unthreaded conduits which are distributed over the periphery of the drive element and which correspond to the appropriate channels in the drive element and in the other element. Either at the same time larger hydraulic amounts or with separate channels different hydraulic functions can be controlled by way of the unthreaded conduits.
Furthermore, the annular hydraulic chamber can be supplied using an actuating piston for movement of the drive element by way of the channels and unthreaded conduits. By using unthreaded conduits, in addition to the aforementioned advantages, channel routing within the drive element can also be simplified, because the unthreaded conduits if necessary enable direct supply of the hydraulic medium to the annular hydraulic chamber.
Advantageously there can be spline-teeth as the nonrotatable connection between the drive element and the other element; they are configured as an unthreaded connection radially within the roller bearing on the neck of the drive element and on the annular projection of the other element. This makes possible a structurally favorable and compact transmission design which moreover yields further simplification of assembly and axial tolerance compensation.
Finally, in one preferred application of the invention the drive element can be a driven pulley set of a continuously variable transmission for motor vehicles and the other element can be the differential gear case of a torsen differential, also known as a worm gear differential, the output to the axle of the motor vehicle extending through the hollow shaft of the pulley set and the transmission ratio of the pulley set to the looping means being controllable by way of channels and the unthreaded conduits. The concept of a torsen differential is known in mechanical engineering and especially in transmission engineering.